Methods, devices and program products are provided for managing a pacing therapy using an implantable medical device (IMD). The methods, devices and program products sense cardiac activity (CA) signals at electrodes located proximate to multiple left ventricular (LV) sites and a right ventricular (RV) site of the heart and utilizing one or more processors to measure activation times between the multiple LV sites and the RV site based on the CA signals. The processors program an order of activation for the multiple LV sites based on the activation times and identify an RV activation time and a septum activation time based on the CA signals. The processors calculate a septum to RV activation time (SRAT) based on the RV and septum activation times and program an AV.sub.SRAT delay based on the SRAT.

A system is provided for controlling a left univentricular (LUV) pacing therapy using an implantable medical device (IMD). The system also includes one or more processors configured to determine an atrial-ventricular (AV) conduction interval (AR.sub.RV) between the A site and a first RV sensed event at the RV site, determine an inter-ventricular (VV) conduction interval (R.sub.LV-R.sub.RV) between a paced event at the LV site and a second RV sensed event at the RV site, and set a ventricular refractory period (VRP) based on at least one of the AV conduction interval or the VV conduction interval and a predetermined offset. The one or more processors are also configured to blank signals over the RV sensing channel during the VRP.

A system and method have at least one implantable lead comprising a right ventricular (RV) electrode and one or more left ventricular (LV) electrodes, at least one processor, and a memory coupled to the at least one processor. The memory stores program instructions. The program instructions are executable by the at least one processor to determine a right ventricular to left ventricular (RV-LV) conduction time representative of a conduction time between a right ventricular (RV) paced event and one or more responsive left ventricular (LV) sensed events, determine a left ventricular to right ventricular (LV-RV) conduction time representative of a conduction time between one or more LV paced event and an RV sensed events, calculate a relation between the RV-LV conduction time and the LV-RV conduction time, and set a pacing mode of an implantable medical device to one of i) a biventricular (BiV) pacing mode and ii) an LV only pacing mode based on the relation between the RV-LV conduction time and the LV-RV conduction time.

Methods, apparatus, and systems are provided to control contraction of the heart. At least one sensing element receives signals indicating electrical activity of sinus rhythm of the heart. Based on the received signals, the progress of contraction of the heart is determined. Based on the progress of contraction, the chamber of the heart may then be stimulated at a plurality of locations. In another embodiment, a plurality of electrodes are implanted in the left ventricle to stimulate at multiple locations in the left ventricle for the purpose of improving hemodynamic performance and increasing cardiac output in a patient who is suffering from congestive heart failure.

VfA cardiac therapy uses an implantable medical device or system. The implantable medical device includes a tissue-piercing electrode implanted in the basal and/or septal region of the left ventricular myocardium of the patient's heart from the triangle of Koch region of the right atrium through the right atrial endocardium and central fibrous body. The device may include a right atrial electrode, a right atrial motion detector, or both. The device may be implanted completely within the patient's heart or may use one or more leads to implant electrodes in the patient's heart. The device may be used to provide cardiac therapy, including single or multiple chamber pacing, atrioventricular synchronous pacing, asynchronous pacing, triggered pacing, cardiac resynchronization pacing, or tachycardia-related therapy. A separate medical device may be used to provide some functionality for cardiac therapy, such as sensing, pacing, or shock therapy.

Systems and methods are provided for detecting arrhythmias in cardiac activity is provided. The systems and methods include measuring conduction delays between an atria (A) and multiple left ventricular (LV) electrodes to obtain multiple intrinsic A/LV intervals, measuring conduction delays between a right ventricular (RV) and the multiple LV electrodes to obtain multiple intrinsic VV intervals. The systems and methods include calculating a first atrial ventricular (AV) delay based on at least one of the intrinsic A/LV intervals, and calculating a second AV delay based on at least one of the intrinsic VV intervals. The systems and methods include selecting a biventricular (BiV) pacing mode or an LV only pacing mode based on a relation between the first and second AV delays, and delivering a pacing therapy based on the selecting operation.

Systems and methods for monitoring and treating patients with heart failure are discussed. The system can store in a memory stimulation parameters, including stimulation timing parameters for a plurality of heart rate ranges. The system includes a plurality of timers with respective durations for the plurality of heart rate ranges. A stimulation control circuit can identify a target heart range in which a detected heart rate falls, and measure an atrioventricular (AV) conduction characteristic value in response to the timer for the target heart range being expired at the detected heart rate. The stimulation control circuit can update a stimulation parameter corresponding to the target heart rate range using the measured AV conduction characteristic. The updated stimulation parameter can be used in cardiac stimulation.

An implantable device and associated method for delivering multi-site pacing therapy is disclosed. The device comprises a set of electrodes including a first and second left ventricular electrodes spatially separated from one another and a right ventricular electrode, all coupled to an implantable pulse generator. The processing circuit coupled to the implantable pulse generator, the processing circuit configured to determine whether a prospective heart failure condition has occurred and if so to trigger the pulse generator to switch from a first pacing mode to a second pacing mode, the first pacing mode comprising delivering only a first pacing pulse to a left ventricle (LV) and thereafter delivering an RV pacing pulse to the right ventricular electrode within a single cardiac cycle and the second pacing mode comprising delivering first and a second pacing pulses to the LV and thereafter delivering an RV pacing pulse to the right ventricular electrode within a single cardiac cycle.

Systems and methods are described herein for evaluation and adjustment of a left ventricular assist device (LVAD). The systems and methods may utilize at least a plurality of external electrodes to monitor cardiac electrical activity before and during LVAD therapy. The cardiac electrical activity as well as other information such cardiac sound information may be used to determine and adjust one or more LVAD output parameters such as pump speed.

In some examples, controlling delivery of CRT includes controlling an implantable medical device to deliver ventricular pacing according to a sequence of different values of a CRT parameter, and acquiring first and second electrograms from respective first and second electrode vectors. For each value of the CRT parameter, a value of a metric of comparison of a first activation interval between occurrences of a first fiducial of a cardiac cycle and a second fiducial of the cardiac cycle detected in the first electrogram to a second activation interval between occurrences of the first fiducial and the second fiducial detected in the second electrogram may be determined. A target value of the metric of comparison may be identified and an updated value of the CRT parameter determined based on the target value. The system then may control the IMD to deliver ventricular pacing at the updated value of the CRT parameter.